A sensitive fluorometric assay for serum monoamine oxidase with kynuramine as substrate.

The detailed procedure of a new sensitive fluorometric assay for human serum monoamine oxidase (MAO) with kynuramine as substrate is described. The data on its reproducibility, stability, correlation with another method, and serum MAO levels for 150 healthy subjects and 205 patients with various diseases, are presented to support the usefulness of this method. Since our method is much simpler and more sensitive than other methods conventionally used, we can recommend it for routine clinical investigation.